NASA gave the Mars Curiosity rover driving commands ahead of its first test-drive across the Martian surface Wednesday, the space agency's field center said.

The 1-ton robotic, car-size rover acknowledged receipt of the instructions for a slow, 30-minute drive that will take the six-wheel nuclear-powered vehicle about 10 feet ahead of where it landed in Gale Crater Aug. 6, the Jet Propulsion Laboratory said.

The rover is then to stop, turn its wheels to the right and then back up in a 90-degree turn, the lab said.

The idea is to move to an area with no known hazards that has already been photographed, Mission Manager Mike Watkins told reporters in a conference call Tuesday.

"We want to park in a place we've exactly examined. We just want to be extra safe," he said.

The rover tested the turning of its wheels Tuesday, with Watkins saying the "wheel wiggle" -- one of which NASA showed in an animated image on its Web site -- was a success.

Curiosity's first longer-distance drive, most likely next month, is to be a quarter-mile trek east-southeast to a spot called Glenelg, which is a natural intersection of three kinds of terrain.

One kind of terrain is layered bedrock, which is attractive as the first drilling target, NASA said.

The slow-speed trip may take as long as two months, with Curiosity staying at Glenelg for a month afterward for experiments, NASA said.

NASA eventually plans to drive Curiosity to Gale Crater's central peak, known as Mount Sharp, 18,000 feet, or 3.4 miles, above the crater's valley.

That mountain is the $2.5 billion mission's primary target for scientific study.

During the conference call, NASA reported scientists discovered a scientific instrument aboard Curiosity was not working properly.

One of two sensors on a weather station called the Rover Environmental Monitoring Station was not sending complete information back to Earth, NASA said.

The REMS, contributed by Spain and Finland, measures humidity, pressure, temperatures, wind speeds and ultraviolet radiation. The sensors are located on two short booms that extend out from the side of the rover's main camera mast.

Scientists suspect the troubled sensor's circuit boards were damaged by small rocks and debris kicked up by Curiosity's landing engines, Deputy Project Scientist Ashwin Vasavada said.

"We will have to be more clever about using the remaining wind sensor to get wind speed and direction," he said.

Watkins added the REMS team was working "pretty hard to understand how to use that remaining, fully operational boom, to best derive wind speed and direction."

Based on measurements so far, Martian air temperatures swing from 28 degrees Fahrenheit to minus 103 degrees Fahrenheit, NASA said.

Ground temperatures change even more between afternoon and pre-dawn morning -- from 37 degrees to minus 132 degrees, NASA said.

"We will learn about changes from day to day and season to season," said Javier Gomez-Elvira of Madrid's Astrobiology Center.